I took a quick look at both of the suggestions. I have to admit I like the no-install bookmarklet version of Iterasi. The possible downside is that it's in beta, with no apparent time line or hint that it's status will change from free to commercial.
Website-Watcher is another story. It appears to be very clear about what it does (which is a lot). The Basic version looks like it does all the heavy lifting most users will need. It's about 30 Euros, and can be tried for free for 30 days.
Both programs can be integrated into FF via extension.
In the bad old days when I used to accumulate hundreds of bookmarks, either of these would have been interesting. (I still get occasional emails from AskSam because of Surf Saver) Now, I only bookmark a few sites that I want to track, rarely more than 60-75. When I get that many, I look through them and eliminate anything not visited for 2-3 months!